Demographic, clinical and laboratory characteristics of hospitalized patients
Table 1 shows the demographic, clinical and laboratory characteristics of hospitalized patients. A total of 273 hospitalized patients diagnosed as COVID-19 were included in this study, with 188 of them were over 60 years old, with an average age of 69.5 years old, and 85 patients were no more than 60 years old, with an average age of 51.0 years old. About half of patients were male both in the elderly patients (50.4%) and the young and middle-aged (55.3%). The prevalence of hypertension in the elderly patients is 58.5%, which is significantly higher than that in the young and middle-aged (36.9%) (P < 0.01). There was no significant difference in the prevalence of diabetes between the elderly (21.7%) and the young and middle-aged patients (14.9%). The median systolic blood pressure of the elderly patients measured on admission was higher than the young and middle-aged patients (133 vs 123 mmHg, P < 0.01), which was consistent with the hypertension history. In addition, the median oxygen saturation showed no difference in two groups (95%).
Table 1
Demographic, clinical and laboratory characteristics of hospitalized patients
Variables | Age ≤ 60y (n = 85) | Age > 60y (n = 188) | P value |
Gender, No(%) | | | 0.81 |
Male | 45 (55.3%) | 95 (50.4%) | |
Female | 40 (44.7%) | 93 (49.6%) | |
Age, years | 51.0 (43, 57)(n = 85) | 69.5 (66, 75.8)(n = 188) | 0.00 |
Hypertension history, No(%) | | | 0.00 |
No | 53 (63.1%) | 141 (41.5%) | |
Yes | 31 (36.9%) | 46 (58.5%) | |
Diabetes history | | | 0.89 |
No | 64 (85.1%) | 101 (78.3%) | |
Yes | 20 (14.9%) | 28 (21.7%) | |
Admission to ICU | | | 0.64 |
No | 69 (81.2%) | 148 (78.7%) | |
Yes | 16 (18.8%) | 40 (21.3%) | |
Systolic blood pressure (SBP), mmHg | 123 (112, 135) (n = 85) | 133 (121, 146) (n = 187) | 0.00 |
Diastolic blood pressure (DBP), mmHg | 77 (68, 86) (n = 85) | 78 (70, 87) (n = 187) | 0.15 |
Oxygen saturation, % | 95 (95, 95) (n = 83) | 95 (94.5, 95) (n = 182) | 0.41 |
Hemoglobin, g/L | 129 (116, 141) (n = 85) | 125 (114, 134) (n = 186) | 0.04 |
Leukocytes, ×109/L | 5.64 (4.47, 7.23) (n = 85) | 5.70 (4.62, 7.78) (n = 186) | 0.31 |
Neutrophil percentage, % | 61.3 (52.3, 71.9) (n = 85) | 71.6 (60.1, 79.9) (n = 186) | 0.00 |
Leukocyte percentage, % | 27.3 (18.1, 34.6) (n = 85) | 19.0 (11.7, 27.4) (n = 187) | 0.00 |
Platelet, ×109/L | 265 (176, 330) (n = 83) | 234 (168, 309) (n = 184) | 0.17 |
ALT, U/L | 23.0 (16.5, 40.0) (n = 85) | 20.0 (13.0, 32.0) (n = 189) | 0.03 |
AST, U/L | 25.0 (18.0, 35.0) (n = 85) | 25.0 (18.3, 36.8) (n = 189) | 0.67 |
Albumin, g/L | 37.6 ± 4.6 (n = 85) | 34.4 ± 4.7 (n = 189) | 0.00 |
Total bilirubin (TBIL), µmol/L | 7.2 (5, 10.1) (n = 85) | 8.0 (6.2, 11.2) (n = 189) | 0.02 |
Direct bilirubin (DBIL), µmol/L | 3.3 (2.4, 4.5) (n = 83) | 3.7 (2.9, 5.5) (n = 189) | 0.01 |
ALP, U/L | 68 (57, 86) (n = 85) | 68 (58, 85) (n = 189) | 0.97 |
GGT, U/L | 27 (19, 55) (n = 85) | 25 (17, 51) (n = 189) | 0.35 |
Blood urea nitrogen (BUN), mmol/L | 4.3 (3.3, 5.4) (n = 84) | 5.0 (4.1, 6.3) (n = 188) | 0.00 |
Creatinine, µmol/L | 64.5 (52.3, 79.8) (n = 84) | 72.0 (60.0, 88.0) (n = 188) | 0.01 |
GFR, ml/min | 101.5 (91.8, 112.2) (n = 84) | 85.7 (68.1, 93.2) (n = 187) | 0.00 |
Procalcitonin (PCT), ng/mL | 0.07 (0.06, 0.18) (n = 36) | 0.08 (0.06, 0.17) (n = 97) | 0.86 |
hsCRP, mg/L | Admission | 9.4 (1.5, 50.6) (n = 85) | 25.9 (2.5, 83.8) (n = 184) | 0.02 |
In hospitala | 3.4 (1.0, 84.7) (n = 58) | 14.9 (2.6, 52.6) (n = 129) | 0.20 |
proBNP, ng/L | 70 (30, 178) (n = 66) | 184 (96, 559) (n = 164) | 0.00 |
cTnI, ng/L | 2.6 (1.9, 9.2) (n = 75) | 6.3 (3.1, 16.0) (n = 168) | 0.00 |
aThe in hospital value of hsCRP is the maximum value collected during hospitalization. |
Among all hospitalized patients, 217 patients (79.5%) were discharged from the hospital and 56 patients (20.5%) were admitted to ICU. Admission to ICU occurred in 21.3% elderly patients and 18.8% young and middle-aged patients, which showed no significant difference.
Laboratory examination on admission revealed that compared with the elderly group, the young and middle-aged hospitalized patients showed higher hemoglobin (HGB) (median, 129 vs 125, P = 0.04), and there was no difference in leukocytes counts (median, 5.64 vs 5.70, P = 0.31) and platelet counts (median, 265 vs 234, P = 0.17). The young and middle-aged patients showed lower neutrophil percentage (median, 61.3 vs 71.6, P < 0.01), higher lymphocyte percentage (median, 27.3 vs 19.0, P < 0.01), higher ALT (median, 23 vs 20, P = 0.03), higher Albumin (mean, 37.6 vs 34.4, P < 0.01), lower total bilirubin (median, 7.2 vs 8.0, P = 0.02) and lower direct bilirubin (median, 3.3 vs 3.7, P = 0.01). Blood urea nitrogen (median, 4.3 vs 5.0, P < 0.01), creatinine (median, 64.5 vs 72.0, P = 0.01) were lower and GFR (median, 101.5 vs 85.7, P < 0.01) was higher in young and middle-aged patients, indicating better renal function reserve. HsCRP in young and middle-aged patients was lower than that in the elderly on admission (median, 9.4 vs 25.9, P = 0.02), but the hsCRP level in both the young and middle-aged patients and the elderly patients reduced significantly during hospitalization (P < 0.01). The maximum hsCRP value in hospital in the young and middle-aged patients was still lower than that in the elderly, but showed no significance (median, 3.4 vs 14.9, P = 0.02). As for cardiovascular function assessment, the levels of proBNP (median, 70 vs 184, P < 0.01) and cTnI (median, 2.6 vs 6.3, P < 0.01) in the young and middle-aged patients were lower than that in the elderly, indicating a greater impairment of cardiovascular function (Table 1).
Characteristics Of Young And Middle-aged Patients
In young and middle-aged patients, 16 patients were admitted to ICU and 69 patients were discharged. Compared with discharged patients, laboratory examination of patients admitted to ICU showed higher leukocytes count on admission (median, 7.4 vs 5.2, P = 0.01) and in hospital (median, 11.8 vs 5.5, P < 0.01), higher neutrophil percentage (median, 82.4 vs 58.1, P < 0.01), lower lymphocytes percentage (median, 6.9 vs 30.1, P < 0.01), and lower platelet count (median, 175.5 vs 278, P < 0.01). The total number of leukocytes in patients admitted to ICU increased significantly during hospitalization (P < 0.01). The patients admitted to ICU had higher ALT (median, 38 vs 22, P = 0.01), higher AST (median, 53.5 vs 21.0, P < 0.01), higher ALP (median, 83.5 vs 67, P = 0.01) and higher GGT (median, 54 vs 24, P < 0.01), lower levels of albumin (median, 33.5 vs 38.9, P < 0.01), higher total bilirubin (median, 9.5 vs 7.1, P = 0.04), direct bilirubin (median, 4.5 vs 3.1, P < 0.01), higher blood urea nitrogen (median, 7.8 vs 4.0, P < 0.01) and higher creatinine (median, 72 vs 64.5, P = 0.01). ProBNP (median, 408 vs 51, P = 0.01) and cTnI (median, 13.0 vs 2.2, P < 0.01) were also higher in patients admitted to ICU than in discharged patients (Table 2).
Table 2
Characteristics of young and middle-aged patients
Variables | Discharged (n = 69) | Admitted to ICU (n = 16) | P value |
Hemoglobin, g/L | 129 (122, 139) (n = 69) | 133 (115, 134) (n = 16) | 0.51 |
Leukocytes, × 109/L | Admission | 5.2 (4.4, 6.4) (n = 69) | 7.4 (5.0, 16.2) (n = 16) | 0.01 |
In hospital | 5.5 (4.7, 6.9) (n = 50) | 11.8 (6.7, 22.5) (n = 12) | 0.00 |
Neutrophil percentage, % | 58.1 (50.5, 65.3) (n = 69) | 82.4 (72.4,88.0) (n = 16) | 0.00 |
Leukocyte percentage, % | 30.1 (24.3, 35.4) (n = 69) | 6.9 (3.9, 15.3) (n = 16) | 0.00 |
Platelet, × 109/L | 278 (211, 334) (n = 67) | 175.5 (127, 305) (n = 16) | 0.03 |
ALT, U/L | 22 (15, 37) (n = 69) | 38 (24, 52.5) (n = 16) | 0.01 |
AST, U/L | 21 (17, 28) (n = 69) | 53.5 (30.5, 67.3) (n = 16) | 0.00 |
Albumin, g/L | 38.9 (35.1, 41.4) (n = 69) | 33.5 (30.2, 37.5) (n = 16) | 0.00 |
Total bilirubin (TBIL), µmol/L | 7.1 (4.9, 9.7) (n = 69) | 9.5 (6.6, 13.6) (n = 16) | 0.04 |
Direct bilirubin (DBIL), µmol/L | 3.1 (2.2, 4.2) (n = 69) | 4.5 (3.3, 7.7) (n = 16) | 0.00 |
ALP, U/L | 67 (55, 82) (n = 69) | 83.5 (66, 126) (n = 16) | 0.01 |
GGT, U/L | 24 (17.5, 48) (n = 69) | 54.0 (32.5, 92.3) (n = 16) | 0.00 |
Blood urea nitrogen (BUN), mmol/L | 4.0 (3.2, 5.0) (n = 69) | 7.8 (5.1, 9.8) (n = 15) | 0.00 |
Creatinine, µmol/L | 64.5 (52.3, 79.8) (n = 84) | 72.0 (60.0, 88.0) (n = 188) | 0.01 |
GFR, ml/min | 102.5 (97.3, 112.1) (n = 69) | 89.7 (74.9, 113.5) (n = 15) | 0.08 |
proBNP, ng/L | 51 (28, 113) (n = 55) | 408 (70, 769) (n = 11) | 0.01 |
cTnI, ng/L | 2.2 (1.9, 6.1) (n = 61) | 13.0 (4.1, 215.4) (n = 14) | 0.00 |
Procalcitonin (PCT), ng/mL | 0.06 (0.05, 0.08) (n = 27) | 0.32 (0.21, 0.62) (n = 9) | 0.00 |
hsCRP, mg/L | Admission | 5.0 (1.05, 19.25) (n = 69) | 89.7 (29.1, 187.8) (n = 16) | 0.00 |
In hospital | 1.35 (0.83, 7.6) (n = 44) | 153 (89.2, 229.8) (n = 14) | 0.00 |
hsCRP variation, mg/L | -2.95 (-16.25, -0.1) (n = 44) | 67.9 (36.9, 77.1) (n = 14) | 0.00 |
As for the inflammatory indicators of young and middle-aged patients who were transferred to ICU, hsCRP (median, 89.7 vs 5.0, P < 0.01) and PCT (median, 0.32 vs 0.06, P < 0.01) were higher than those of discharged patients on admission, and the hsCRP variation of young and middle-aged patients admitted to ICU was 67.9 mg/L, indicating hsCRP increased during hospitalization, while hsCRP variation of discharged patients was − 2.95 mg/L indicating decreased hsCRP. The hsCRP variation in patients admitted to ICU was significantly higher than that in discharged patients (P < 0.01).
Characteristics Of Patients Admitted To Icu
Among the patients admitted to ICU, characteristics are showed in Table 3. The mean age of young and middle-aged patients was 50.8 years old and that of the elderly patients was 75.7 years old. The comparison between young and middle-aged patients and the elderly found that the systolic blood pressure (median, 119 vs 137, P = 0.01) and diastolic blood pressure (mean, 73.9 vs 82.4, P = 0.03) of the young and middle-aged patients were significantly lower than that of the elderly. The young and middle-aged patients showed higher ALT (median, 38 vs 20, P = 0.01), higher GGT (median, 54 vs 25, P < 0.01) and higher GFR (median, 89.7 vs 72.7, P = 0.01). The proBNP level of young and middle-aged patients was lower than that of the elderly (median, 408 vs 999, P < 0.01). Young and middle-aged patients showed higher PCT than elderly patients (median, 0.32 vs 0.18, P < 0.01), and there was no difference of hsCRP (median, 89.7 vs 103.7, P < 0.01) at the time of admission between the young and middle-aged patients and the elderly patients who were admitted to ICU. However, the maximum hsCRP value in hospital of young and middle-aged patients was significantly higher than the elderly patients (median, 153 vs 65.2, P < 0.01), as well as the hsCRP variation during hospitalization (median, 67.9 vs -10.2, P < 0.01).
Table 3
Characteristics of patients admitted to ICU
Variables | Age ≤ 60y (n = 16) | Age > 60y (n = 40) | P value |
Age, y | 50.8 ± 11(n = 69) | 75.7 ± 7.6(n = 16) | 0.00 |
Systolic blood pressure (SBP), mmHg | 119 (106, 135) (n = 16) | 137 (127, 151) (n = 38) | 0.01 |
Diastolic blood pressure (DBP), mmHg | 73.9 ± 15.1 (n = 16) | 82.4 ± 12.2 (n = 38) | 0.03 |
ALT, U/L | 38 (24, 52.5) (n = 16) | 20 (15, 33) (n = 38) | 0.01 |
TBIL, µmol/L | 9.5 (6.6, 13.6) (n = 16) | 11.2 (7.9, 16.4) (n = 38) | 0.23 |
ALP, U/L | 83.5 (66, 126) (n = 16) | 67 (58.5, 88) (n = 38) | 0.09 |
GGT, U/L | 54.0 (32.5, 92.3) (n = 16) | 25.0 (16.3, 39.0) (n = 38) | 0.00 |
Blood urea nitrogen (BUN), mmol/L | 7.8 (5.1, 9.8)(n = 15) | 6.5 (5.0, 11.6) (n = 37) | 0.96 |
Creatinine, µmol/L | 79 (52, 104) (n = 15) | 79 (64, 116.0) (n = 37) | 0.40 |
GFR, ml/min | 89.7 (74.9, 113.5) (n = 15) | 72.7 (51.4, 88.8) (n = 37) | 0.01 |
proBNP, ng/L | 408 (70, 769) (n = 11) | 988 (681, 4285) (n = 27) | 0.01 |
Procalcitonin (PCT), ng/mL | 0.32 (0.21, 0.62) (n = 9) | 0.18 (0.10, 0.30) (n = 22) | 0.03 |
hsCRP, mg/L | Admission | 89.7 (29.1, 187.8) (n = 16) | 103.7 (46.9, 142.7) (n = 37) | 0.76 |
In hospital | 153 (89.2, 229.8) (n = 14) | 65.2 (43.6, 111.9) (n = 35) | 0.00 |
hsCRP variation, mg/L | 67.9 (36.9, 77.1) (n = 14) | -10.2 (-29.6, 12.7) (n = 35) | 0.00 |
Risk factors for ICU admission in the young and middle-aged and the elderly patients
In young and middle-aged patients, Table 4 shows that the increase of hsCRP variation was significantly correlated with the increased risk of ICU admission. After excluding the interference of GFR, ALT and proBNP by multivariate logistic analysis, hsCRP variation was still an independent risk factor for ICU admission, and OR value was 1.068. Table 4 also shows that the increase of proBNP was correlated with the risk of ICU admission in the elderly patients (OR = 1.026), while hsCRP variation was not related to the risk of ICU admission in the elderly. The OR values of different variables for ICU admission in the young and middle-aged people and the elderly people are shown in Fig. 1 respectively.
Table 4
Association between hsCRP variation and risk of ICU admission in patients
Age ≤ 60y | Age > 60y |
Model | Odds Ratio (95% CI) | Model | Odds Ratio (95% CI) |
Model 1 | 1.066 (1.032, 1.100) | Model 1 | 1.009 (1.005, 1.014) |
Model 2 | 1.064 (1.029, 1.100) | Model 2 | 1.028 (1.014, 1.043) |
Model 3 | 1.068 (1.025, 1.113) | Model 3 | 1.026 (1.011, 1.042) |
Model 1- hsCRP variation Model 2- hsCRP variation, proBNP Model 3- hsCRP variation, GFR, ALT, proBNP | Model 1- proBNP Model 2- hsCRP variation, proBNP Model 3- hsCRP variation, GFR, ALT, proBNP |
Prediction of hsCRP variation on ICU admission in young and middle-aged patients
Figure 2 shows the ROC curve of hsCRP variation for ICU admission in young and middle-aged patients. The area under the curve of hsCRP was 0.925 (P < 0.001) in young and middle-aged patients, which was statistically significant, indicating that hsCRP was significant for the prediction of ICU admission in young and middle-aged patients. The optimal cut-off value was 13.2 mg/L, with sensitivity of 92.9% and specificity of 95.5%. The area under the curve in the elderly was 0.528 (P = 0.632), which had no statistical significance. Therefore, the hsCRP variation in the elderly had no predictive significance. After comparing the AUC of the two curves, AUC in young and middle-aged patients was greater than that in the elderly patients (Z = 4.49, P < 0.001).